Cell Structure Flashcards
What are the features of eukaryotic cells?
- cytoplasm
- plasma membrane/ cell surface membrane
- membrane bound organelles
Define membrane bound organelles
Organelles which are covered by a membrane to keep them separate from the rest of the cell
State the membrane bound organelles present in a eukaryotic cell
- nucleus
- rough and smooth endoplasmic reticulum
- golgi apparatus
- mitochondria
- lysozymes
- cilia and undulipodia
- chloroplasts
- vacuole
What sub-cellular structures contain their own DNA?
- nucleus
- mitochondria
- chloroplasts
State the different parts that make up the nucleus
- nuclear envelope
- nucleolus
- chromatin
What is the function of the nuclear envelope?
- Separates the contents of the nucleus from the rest of the cell
- double membrane, contains pores
- at points wherein the inner and outer membranes fuse, dissolved substances can pass through
- pores enable larger substances (such as mRNA and hormones) to enter and leave the nucleus
What is the function of the nucleolus?
- ribosomes are made here
- no membrane around it
- contains RNA
What is the function of the chromatin?
Genetic material (DNA & histone proteins) condense to chromosomes during division
What is the difference between chromatin when the cell is dividing and when its not dividing?
- when cell is not dividing, chromatin is spread out or extended
- when cell is about to divide, chromatin condenses and coils tightly into chromosomes
State the components of the rough endoplasmic reticulum
- cisternae
- ribosomes
What are the cisternae?
Series of flattened sacs
What is the function of cisternae?
Form channels to transport substances
What is the function of the ribosomes?
- protein synthesis occurs and proteins pass through the cisternae to Golgi Apparatus OUT of the cell
- RER has a large surface area for ribosomes
What is the difference between the rough ER and the smooth ER?
Rough ER has ribosomes on its surface, whereas smooth ER does not
What is the function of the cisternae in the smooth ER?
- continuous with nuclear membrane to transport lipids
- contains enzymes that catalyse reactions involved in lipid metabolism and synthesis, and carbohydrate metabolism
Describe the Golgi Apparatus
Series of fluid filed flattened and curved sacs, with vesicles surrounding the edges
What are the components of the Golgi Apparatus?
- stack of membrane flattened sacs
- vesicles
- secretory vesicles
What is the function of the stack of membrane bound flattened sacs?
Proteins modified by adding sugar to make glycoproteins or lipids to make lipoproteins
What is the function of the vesicles?
contains proteins that fuse with the Golgi apparatus
What is the function of secretory vesicles?
Take modified proteins out of the golgi apparatus
What is the overall function of the golgi?
Processes and packages proteins and lipids
What is the difference between secretory vesicles and transport vesicles?
- secretory vesicles store and release materials into the cell or to the extracellular environment
- whereas transport vesicles move materials within the cell
What are the components that make up mitochondria?
- outer membrane
- inner membrane that folds into cristae
- inner part of mitochondrion is a fluid filled matrix
What is the function of mitochondria?
It is the site of ATP production during aerobic respiration
Why can mitchondria come in different shapes?
Depends on how the cell has been cut, for example if cut through the top middle the mitochondria may appear circular, but if cut through the side middle, the mitochondria may appear rod-shaped
What are the different shapes that mitochondria can come in?
- spherical
- rod-shaped
- branched
What are lysozymes?
- small bags formed in the golgi
- surrounded by a single membrane
What is the function of a lysozyme?
Contains powerful hydrolytic enzymes to digest and engulf substances/ organelles